Lens Fogging & Condensation: Clear The Fog And Capture The Shot

Have you ever noticed the fogging on your lenses when you are outside? It’s an annoying phenomenon that most have experienced at least once. For photographers, lens fogging can be a significant problem that can ruin the perfect shot. 

Understanding the science behind lens fogging and learning how to prevent and cure it can help to ensure that you always have a clear view and the ability to capture the perfect shot.

Why Is My Camera Lens Foggy? What Causes Lens Fogging?

Fogging on lenses is caused by condensation, which occurs when the lens temperature is at or below the dew point. The current temperature and the relative humidity in the air determine the dew point. When the temperature of the lens is at or below the dew point temperature, condensation forms on the lens, creating a foggy appearance.

Remember that the dew point constantly changes and will vary as temperatures and humidity fluctuate.

Dew Point Info

Preventing a foggy lens is relatively easy if you understand the underlying science. Simply keep the temperature of the gear above the dew point, and you’re all set. However, this is often easier said than done. It’s not always practical or possible to look up the dew point and precisely measure ambient room or interior vehicle temperatures.

But when you know both, it’s an excellent way to figure out if you’re going to run into a fogging issue when you go outside. It’s also important to remember that the dew point is a moving target and changes as temperatures and humidity fluctuate.

Tips To Prevent Fogging On A Camera Lens

You can take several steps to prevent fogging on your lenses and ensure that you’re always able to capture clear and sharp images.

1. Keep The Lens and Camera Warm

One of the most effective ways to prevent fogging is to keep the room, car, or other space where you store your gear as warm as you can tolerate. The temperature of your equipment should ideally be the same as the outside air or as close as possible to it. 

When you’re storing your gear in a cool or cold environment, it’s more likely to fog when you take it outside. Keep your gear stored in a warm and well-ventilated area. If you’re traveling with it in your car, keep the temperature in the car on the warmer side, or keep the gear in the trunk.

2. Store The Lens in an Area Without Air Conditioning

Another tip is to store your gear in an area without air conditioning when possible. This is because air conditioning can significantly lower the temperature of a room as well as reduces humidity, which can lead to fogging. 

When you’re in a hotel or at home, try to store your gear in a bathroom or closet that doesn’t have air conditioning or in a room with all the vents shut. This can help to prevent fogging by keeping the temperature of the gear as close as possible to the outside air.

3. Use a Hair Dryer to Warm the Lens

If you’re worried that your lens will fog, you can use a hair dryer to gently warm up your gear before you go outside. Make sure not to make it hot, but just comfortably warm. By raising the temperature of the gear to higher than the dew point, it won’t fog, and in most cases, it only takes a few degrees difference. 

Warm everything up and not just the front element, or the rest of the lens may be cool enough to drop the temp of the front element back down below the dew point once you go back outside.

4. Put the Lens & Camera Outside

Another tip to prevent fogging is to set your gear outside to warm up gradually. A good approach is to do so 30 minutes to an hour before you need it, but make sure to do it in a safe place. This can also be helpful if your shoot is in the evening and you’re worried about fogging with gear stored inside a chilly house or hotel room.

That said, it is important to be aware of your surroundings and take security measures when storing your gear outside or in a hotel parking lot. Remember never to leave your camera gear unattended and always be careful about potential break-ins.

Fogged Canon Camera Lens

Precautions If Your Lens Is Foggy And Has Condensation 

Fogging on lenses can be a frustrating problem, but there are some precautions you should take as not to cause further damage in these conditions. If you find yourself in a situation where your lens is fogged, there are a few steps you can take to prevent damaging your camera and lens. If you need general guidance on how to prevent damage your camera and lens, read this.

1. Leave the Lens on the Camera

First, it’s essential not to remove the lens or body cover from the camera. The reason for this is that you don’t want the innards of your camera covered in condensation. Temporary condensation on the surface of your gear is usually not a big deal, but you don’t want any excess moisture forming on the inner surfaces of your camera or lens. 

If you see fog on your lens or any hint of condensation on the camera body, keep everything capped, and don’t take the lens off the camera if it’s already attached.

2. Don’t Wipe the Lens

Second, it’s best to forget about wiping off the lens to clear the condensation. Remember, the reason we have condensation, also known as fogging, is that the temperature of the lens is cool enough to allow it to happen. If you wipe it off, it’s only going to come right back. 

Also, removing a fogged UV filter isn’t a cure. As soon as it’s off, the front element will start to fog up.

The other potential issue with wiping the lens is that if there are any bits of grit, you’ll drag them around the surface, which can lead to scratches across the front element. Here’s how to properly clean your lens.

Also, here’s an article I wrote talking about using lens wipes.

Picture taken with fogged lens

How Do You Fix A Foggy Lens?

So, how do we defog the gear? 

1. Take the Camera Back Inside

One of the most effective ways is to head back to a warm and well-ventilated area and use a hair dryer to gently warm up your gear. If there’s no hair dryer in sight, you can allow your gear to acclimate naturally by keeping it in your camera bag. 

You can also take the gear out and put it in the sun or in front of an air conditioner condenser unit to warm it up faster.

2. Wrap Warmers Around the Lens

Another option is to strap hand warmers around the lens with rubber bands and let it heat up gradually. This can be unsightly, but it does work.

3. Warm the Lens With a Car Heater

You can also warm a foggy lens using a car heater by cranking it all the way up and blasting warm air onto the gear. However, keep in mind that this may not be comfortable, but it will cut down the defogging time considerably.

Camera in a Ziploc Bag

4. Place the Camera and Lens in a Sealed Bag

Another way is to place your gear in sealed bags, like a Ziploc, before heading outside. This will help keep any condensation to a minimum since the air in the bag will have less moisture than the more humid outside air.

The idea behind all these methods is to get the gear at least warm enough so it’s no longer fogging up and, ideally, bring it close to the ambient outside temperature. Any way you can get there safely is just fine.

Fogging on lenses can be frustrating, but by understanding the causes and taking preventative measures, you can avoid the problem altogether. 

If you find yourself in a situation where your lens is fogged, there are several steps you can take to remedy the problem, such as using a hair dryer to gently warm up your gear, allowing your gear to acclimate naturally, or warming the gear using a car heater or hand warmers. 

Remember, the key is to get the gear at a temperature above the dew point so that it’s no longer fogging up, and ideally, get it close to the ambient outside temperature.

Cold Weather Camera Lens Fogging

Cool weather fogging is the opposite problem of lens fogging caused by humidity. It occurs when you’re out in the cold, and everything fogs up as soon as you go back indoors. 

In this case, it depends on whether your gear is in a bag. If it is, you can simply bring in the bag, not open it for a few hours, and let it acclimate slowly and gradually. This is what many photographers do, with no ill effect. 

For most photographers, we don’t always need immediate access to the gear once we’re done outside for the day. Of course, make sure to grab your memory cards first so you don’t open the bag once indoors.

Another option is to grab a Ziploc bag if your camera fits and seal it in there while you’re still outside. This can be done for additional protection by helping to cut down on the potential for condensation once you go indoors. 

If you want to go to extremes, you can grab some silica gel packs and toss them into the bag with your gear.

If you need your gear in a hurry once you’re back indoors, the same rules apply as before. You need to warm the gear up enough to prevent condensation. 

One trick is to warm it up in the car on your way home before bringing it back inside. Another method is to place your zipped camera bag in front of a space heater and allow it to warm the bag gradually. It probably doesn’t need to be said, but keep your gear a safe distance from the heater so that it doesn’t melt the nylon bag or cause a fire hazard.

Another way is to place your gear into sealed bags outside and bring it in that way, then warm it through the bag by placing it over a heater vent on the floor or near but not right on top of a space heater, or you can try the hair dryer method again. This way, you don’t have to warm the camera bag first, and it can save a lot of time.

Final Words

At any rate, the bottom line is that to avoid fogging in any conditions or temperature, you should keep the gear warmer than the dew point, either inside or out. If you already have fogging, you should warm the lens up as quickly and safely as possible. 

By following these tips and being prepared, you can minimize the chances of experiencing lens fogging in cold weather and ensure that you’re always able to capture clear and sharp images.

Additional Resources:
Canon Community
Creative Raw

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